1. Field of the Invention
This invention relates to a device for measuring the compressive load developed by a bolt or clamping device during the tightening procedure. More particularly, this invention relates to a device for measuring the maximum clamping force of a bolt or like clamping device so that during use such bolt can be tightened to the maximum to render it more resistant to fatigue failure. The device of this invention is also useful in demonstrating to field personnel proper bolt tightening techniques, and the effects of oils and like substances on the bolt's clamping force and the torque required to tighten the bolt to the maximum.
2. Prior Art
Bolts, as for example, stove bolts (with and without cotter pins), carriage bolts, machine bolts, eye-bolts, plow bolts and the like are metal pins or rods for fastening objects together. A bolt usually has a head at one end and is helically or spirally threaded along all or a portion of its length. The bolt is usually secured by means of a threaded nut which is attached to the bolt at the end opposite the head by rotation about the longitudinal axis of the bolt.
Heretofore, several disadvantages have been associated with the use of bolts as fastening devices, especially with regard to the incidence of bolt failure due to metal fatigue. For example, it is often very difficult to adequately determine under actual use conditions when a nut and bolt assembly has been tightened to the maximum. This is crucial information in that it provides an indication as to the actual clamping force exerted by the nut and bolt assembly and indicates when the assembly is most resistant to fatigue failure. This information also indicates when further tightening should be discontinued so as to prevent structural deformation and weakening of the bolt. A further disadvantage associated with the conventional use of nut and bolt assemblies is the strength of materials used in the construction of such assemblies.
Thus, it is an object of this invention to provide a means for determining or measuring the maximum clamping force of a bolt and nut assembly under actual use conditions, and the strength of materials used in bolt and nut construction. It is also an object of this invention to provide a teaching device for demonstrating to field personnel proper bolt tightening techniques, and the effects of oils and like substances on the bolt's clamping force and the torque required to tighten the bolt to the maximum. Other objects and advantages of this invention will be apparent from the following specification and claims.